I woke up this morning to find Bo extremely lethargic and skittish- exactly the OPPOSITE of how he's ever been with me so far. He's usually up and about before I even get up, and I feed him first thing in the morning. However, this morning he wasn't moving around... he's either still, hiding in his little house that he always swims through and NEVER sits in, or he's avoiding me. I spotted pale-looking skin on his head and I'm unsure if I'm being paranoid or if I have an issue I need to take care of... would you mind please helping him?

Housing
What size is your tank? 2.5 gallon
What temperature is your tank? 78 degrees
Does your tank have a filter? No..
Does your tank have an air stone or other type of aeration? No
Is your tank heated? Yes
What tank mates does your betta fish live with? A plant (Anubias Nana)

Food
What type of food do you feed your betta fish? Aqueon Betta Pellets
How often do you feed your betta fish? 2-3 pellets a day

Maintenance
How often do you perform a water change? 50% on Wednesdays and 100% on Saturdays thus far.
What percentage of the water do you change when you perform a water change? 50-100%
What type of additives do you add to the water when you perform a water change? BettaSafe Water Dechlorinator

Water Parameters:
Have you tested your water? Not yet- but I plan to take a sample as soon as I'm home from school. His water is dechlorinated tap water.

Symptoms and Treatment
How has your betta fish's appearance changed? Slight tears on his fins; losing a bit of coloration around the face- he's a little paler.
How has your betta fish's behavior changed? Now hiding in his house as opposed to being his energetic self... he dashes away when he sees me!
When did you start noticing the symptoms? This morning.. an hour ago...
Have you started treating your fish? If so, how? No; I don't want to hurt his kidneys if I can help it.
Does your fish have any history of being ill? Not that I know of.
How old is your fish (approximately)? I'm unsure; he's been with me since January 18th.

Please please please help if you can- I've already been through the disease and treatment stickies but I'm still very unsure. And this change was so drastic, I'm afraid that Bo may die... please help us. Thank you! I'll be on to check throughout the day...

Thank you so much,

Caii and Bo

P.S.- these were the only good shots I was able to take of him this morning. Thank you!

How soon did this happen after a water change and if it was 100% water changes-how did you acclimate back to the tank.

What I would recommend at this point-make a 50% water only and use double dose dechlorinater-leaving him in the tank for the water change-Double check your temp with an independent thermometer. Also, you might want to check the heater for cracks-since a stray volt can cause behavior changes like this too-especially after a water change and you didn't let the heater cool off long enough or forgot to unplug. If it is osmotic shock or too long in chlorinated water-sadly it can be fatal within 72h and not a lot you can do.

How soon did this happen after a water change and if it was 100% water changes-how did you acclimate back to the tank.

What I would recommend at this point-make a 50% water only and use double dose dechlorinater-leaving him in the tank for the water change-Double check your temp with an independent thermometer. Also, you might want to check the heater for cracks-since a stray volt can cause behavior changes like this too-especially after a water change and you didn't let the heater cool off long enough or forgot to unplug. If it is osmotic shock or too long in chlorinated water-sadly it can be fatal within 72h and not a lot you can do.

Good luck and keep us posted...

Thank you for your swift response!

This happened a day after the 100% water change- I do my full changes on Saturdays. I acclimated him by putting in a cup of the new water in his holding tank of the old water over a period of two hours, then slid him gently in his new tank once that was over.

Double dose dechlorinator? A double amount or a new product? I'm afraid to double up on the dechlorinator- can that hurt him? I'll take the heater out of his tank when I get home this evening and examine it, though I'm a bit leery of that because as part of the water change, I unplug it and let it sit in Bo's holding tank to keep him a little warmer while I'm changing the water.

I don't know what osmotic shock is, but I'll look it up... I changed a small amount of his tank water this morning before I left, but should I do that once again when I get home?
What else can I do?

It is hard to overdose dechlorinating products unless you use an extreme amount or if it is the type that uses other additives for slime coat, wound bandage-like aloe and even then, you need a lot of it to cause any problems

As a general rule, anytime you have a behavior change-especially after a water change-Make a partial water change with like temp double dosed dechlorinted water-even if you just did one.

If you unplugged the heater and allowed it to cool off properly-I wouldn't worry about it....that was just a precaution....Not everyone knows the importance of heater care with water changes and it sound like you have a good understanding....

Osmotic shock can happen with sudden extreme chemistry changes-but it sounds like you properly acclimated him and so hopefully that is not the problem.

It is hard to overdose dechlorinating products unless you use an extreme amount or if it is the type that uses other additives for slime coat, wound bandage-like aloe and even then, you need a lot of it to cause any problems

As a general rule, anytime you have a behavior change-especially after a water change-Make a partial water change with like temp double dosed dechlorinted water-even if you just did one.

If you unplugged the heater and allowed it to cool off properly-I wouldn't worry about it....that was just a precaution....Not everyone knows the importance of heater care with water changes and it sound like you have a good understanding....

Osmotic shock can happen with sudden extreme chemistry changes-but it sounds like you properly acclimated him and so hopefully that is not the problem.

Alright- I'll do a 25% water change with a double dose of dechlorinator when I get home (is that a safe move? Or should I do a 50%? I'm just a bit worried because water changes seem to stress him out greatly); I also intend to got to PetSmart with a water sample to get it tested and then I'll update from there.

That will be fine, however, I would wait at least 12h-and better 24h after a water change to test the water. When you do have it tested, watch them do it and get numbers-don't accept "Fine"

Yes ma'am!
If I may, though- why should I wait 12-24 hours? If Bo's being hurt by it (even if he's not) wouldn't it be best to test it right away? Or should I quarantine Bo in a half-gallon container until I can test the water?

Have you gotten back to check on him again?
I was hoping that maybe he was a little shocked by lights turning on... Did you notice this right after turning on his lights? Sometimes my bettas get groggy when I wake them up suddenly with the lights. I really hope this is the case.

Thank you so much for your help- I'm sorry the update took so long, but here it is!

After school yesterday I rushed home to check on Bo- he was still lethargic, but I immediately did a 50% water change and double-dosed like Oldfishlady suggested.

The results were IMMEDIATE! Bo began becoming more active, and even came to approach me at the front of his tank. I tested him with a pellet to see if he had his appetite back, and it was back in full-throttle! XD
I fed him 4 pellets, made sure everything was kosher, then went to PetSmart. I arranged to have my water tested on Friday, and finally got around to purchasing some API Stress Coat. I also started looking for tank lights, so that Bo would have a set light/dark schedule that wouldn't stress him out.

This morning he was up and active as usual, and I was so relieved! I skimmed some water out of the tank and added some new properly conditioned tap water just to make sure he was alright. (Probably unnecessary but I'm still paranoid!)

As of this morning, Bo was his normal self- we played with a homemade toy that he seems to like, he ate, swam around and his color seemed to have improved overnight.

Hopefully, the problem is sufficiently solved and Bo's back to being healthy.